Borelli (De motu animalium, Rome, 1680), explained that birds are enabled to grasp the twig on which they rest whilst sleeping, without having to make any muscular exertion, because the weight of the body bends the knee and ankle-joints, over both of which pass the tendons of this compound muscle.
If the budget be not sanctioned by the emperor, that of the previous year remains in force, and the government has power, motu proprio, to impose the extra taxes necessary to carry out new laws.
His best-known work is De motu animalium (Rome, 1680-1681), in which he sought to explain the movements of the animal body on mechanical principles; he thus ranks as the founder of the iatrophysical school.
His publications include: Disquisitio mathematica in causam physicam figurae et magnitudinis terrae (Milan, 1751); Saggio della morale filosofia (Lugano, 1 753); Nova electricitatis theoria (Milan, 1 755); Dissertatio de motu diurno terrae (Pisa, 1758); Dissertationes variae (2 vols.
And on the 21st of November 1907 a papal motu proprio declared all the decisions of the Biblical Commission, past and future, to be as binding upon the conscience as decrees of the Roman Congregations.